:root {
  --bg: #1a1a2e;
  --bg-card: #16213e;
  --bg-input: #0f3460;
  --accent: #e94560;
  --accent-hover: #ff6b81;
  --text: #eee;
  --text-muted: #a0a0b0;
  --radius: 12px;
  --max-width: 800px;
  --safe-top: env(safe-area-inset-top, 0px);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
  --safe-left: env(safe-area-inset-left, 0px);
  --safe-right: env(safe-area-inset-right, 0px);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  padding: var(--safe-top) var(--safe-right) var(--safe-bottom) var(--safe-left);
  line-height: 1.5;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem 1rem;
}

/* Header */
.header {
  text-align: center;
  margin-bottom: 2rem;
}

.header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: .25rem;
}

.header p {
  color: var(--text-muted);
  font-size: .95rem;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  color: var(--accent);
  text-decoration: none;
  font-size: .9rem;
  margin-bottom: 1rem;
}

.back-link:hover {
  color: var(--accent-hover);
}

/* Tool grid */
.tool-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 500px) {
  .tool-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 768px) {
  .tool-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.tool-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .75rem;
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 1.5rem 1rem;
  text-decoration: none;
  color: var(--text);
  transition: transform .15s, box-shadow .15s;
}

.tool-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0,0,0,.3);
}

.tool-card .icon {
  font-size: 2.5rem;
}

.tool-card .name {
  font-weight: 600;
  font-size: 1.05rem;
}

.tool-card .desc {
  color: var(--text-muted);
  font-size: .85rem;
  text-align: center;
}

/* Form elements */
.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  font-size: .85rem;
  color: var(--text-muted);
  margin-bottom: .4rem;
  font-weight: 500;
}

select, input[type="number"] {
  width: 100%;
  padding: .75rem 1rem;
  background: var(--bg-input);
  color: var(--text);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: var(--radius);
  font-size: 1rem;
  appearance: none;
  -webkit-appearance: none;
}

select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%23a0a0b0' stroke-width='2' fill='none'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 2.5rem;
}

select:focus, input:focus {
  outline: none;
  border-color: var(--accent);
}

/* Results */
.results {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-top: 1.5rem;
}

.results h2 {
  font-size: 1.1rem;
  margin-bottom: 1rem;
  padding-bottom: .5rem;
  border-bottom: 1px solid rgba(255,255,255,.1);
}

.result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: .5rem 0;
}

.result-row + .result-row {
  border-top: 1px solid rgba(255,255,255,.05);
}

.result-label {
  color: var(--text-muted);
  font-size: .9rem;
}

.result-value {
  font-weight: 600;
  font-size: 1rem;
}

.result-value.highlight {
  color: var(--accent);
  font-size: 1.3rem;
}

.fuel-bar {
  margin-top: 1rem;
}

.fuel-bar-track {
  height: 2rem;
  background: var(--bg);
  border-radius: .5rem;
  overflow: hidden;
  display: flex;
}

.fuel-bar-segment {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .7rem;
  font-weight: 600;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,.5);
  min-width: 0;
  overflow: hidden;
  white-space: nowrap;
}

.fuel-bar-legend {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin-top: .5rem;
  font-size: .8rem;
}

.fuel-bar-legend span {
  display: inline-flex;
  align-items: center;
  gap: .3rem;
}

.fuel-bar-legend .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}

.empty-state {
  text-align: center;
  color: var(--text-muted);
  padding: 2rem 1rem;
  font-size: .95rem;
}